Pull off and discard tomatillo hulls. Rinse tomatillos and set one aside. Place remaining tomatillos, onions (don’t peel onions if you want sauce to have a mild roasted flavour), and chili in a 10-12 inch frying pan. (Use an old pan; this process tends to discolour the surface – I use an old cast iron frying pan.) Shake pan or turn veggies frequently until they are charred all over, about 15 minutes. Tomatillos should be soft when pressed.

Let vegetables cool. Peel onions if roasted in their skins. Pull loose skin from chili and discard; also cut out and discard stem and seeds.

In a food processor or with a knife, mince uncooked tomatillo; roasted tomatillos, onions, and chili; and cilantro. Season mixture to taste with lime juice and salt. Serve, or if making ahead, cover and chill up to 4 days.

Superb with grilled meat and poultry, also a refreshing dip for tortilla chips. A big spoonful or two may also be mixed with a mashed ripe avocado, add more lime and salt to taste.